Known in the art is a gravity concentrator (U.S. Pat. No. A. 4,157,951) comprising a hollow casing which extends vertically and has a pipe for the admission of a separating fluid provided at the bottom end of the casing, a pipe for discharging the separating fluid and light fraction provided at the top end of the casing, and a pipe for discharging heavy fraction provided at the bottom end of the casing.
A material being treated is loaded into the gravity concentrator together with the separating fluid. An upward flow of the material being treated moving from the pipe for the admission of the separating fluid towards the pipe for discharging light fraction is created in the casing owing to the supply of the separating fluid. The light fraction is moved upwards by the flow of the material being treated and is discharged through the pipe for discharging light fraction, and heavy fraction with a higher specific gravity is concentrated in the bottom part of the casing and is discharged through the pipe for discharging heavy fraction.
The prior art concentrator is suitable for the separation of a classified material being concentrated. Only a laminary upward flow of the material being treated is created in the casing of the gravity concentrator so that a part of heavy fraction cannot be suspended. The possibility of obtaining high-grade concentrate is thus lowered. The effect of friction between particles of the material being treated and the inner surface of the casing is not used in the prior art gravity concentrator, and fine particles of heavy fraction are lost from the gravity concentrator with the upward flow of the material being treated.
The prior art gravity concentrator does not have any provision for imparting additional pulsations to the separating fluid and material being treated under restricted conditions so that efficiency of separation of the material being concentrated is low.
Also known in the art is a gravity concentrator (GB, A, 2,003,756) comprising a hollow cylindrical casing extending in an inclined position and having a partition dividing the casing into two conjugated chambers communicating with each other through a pipe provided in the partition and extending coaxially with the longitudinal axis of the casing. The top end of the casing has a pipe for supplying a material being treated, and the bottom end of the casing has a pipe for discharging heavy fraction.
The whole body of material being treated in the prior art gravity concentrator is suspended in a steady turbulent flow so that high-grade separation of heavy and light fraction particles cannot be ensured.
The prior art gravity concentrator cannot ensure pulsations of the separating fluid and material being treated under confined conditions so that efficiency of separation of the material being concentrated is low.
Known in the art is a gravity concentrator GB, A, No. 2,164,589) comprising a hollow casing extending in an inclined position for receiving a material being treated and having a pipe for supplying the material being treated, a pipe for supplying a separating fluid, and pipes for discharging light and heavy fractions of the material being treated.
The prior art gravity concentrator provides for the creation of a number of successive turbulent zones in which separation of heavy and light fractions occur. Fine particles of heavy fraction do not have time to move to the bottom of the gravity concentrator because of the steady turbulence and are lost with light fraction. The hydrodynamic conditions of separation of fractions of the material being concentrated cannot thus be optimized, namely, a pulsating flow of the material being treated with local turbulence under confined conditions cannot be created.